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41.
42.
Recent research has suggested that the fate of biologically active compounds (BACs) originating from point sources such as wastewater treatment plants is fundamentally different from that of similar compounds released from nonpoint sources through runoff from agricultural landscapes. Downstream from wastewater treatment plants, BACs will degrade via a variety of mechanisms; however, their concentration in the water adjacent to the point of discharge may not decrease over time, as the compounds are continually released. In contrast, in agricultural systems, BACs are episodically introduced to surface water during snowmelt and rainstorm events, and under these circumstances, may be found in water for only hours or days after a storm event. Recent research in our laboratories as well as others, has suggested that sediments play an important role in the persistence of herbicides and steroids in watersheds after nonpoint source loading events. Conceptually, the sediment serves as both a sink and a source, equilibrating with BACs during storm events then slowly releasing them back into the water over time, long after the initial pulse of chemicals has moved downstream.  相似文献   
43.
Although bycatch of seabirds and other long-lived species is a critical conservation issue in world fisheries, case studies documenting significant reductions in the mortality of these low-productivity species in a fishery are rare. We studied progress toward seabird conservation in the Alaskan longline fisheries, one of the largest and most diverse demersal fisheries. We generated annual seabird bycatch rates in 4 target fisheries and all fisheries combined from 23 years of fisheries observer data. We used 0-inflated negative binomial models to evaluate variables influencing seabird bycatch per unit effort (BPUE) in 2 target fisheries. Following adoption of streamer lines, at first voluntarily and then mandatorily, seabird BPUE was reduced by 77–90%, preventing mortality of thousands of birds per year. Despite this, BPUE increased significantly in 2 of 4 target fisheries since streamer lines were adopted. Although night setting yielded significant reductions (74–97%) in seabird BPUE and significant increases (7–11%) in fish catch per unit effort over daytime setting, nighttime setting increased the BPUE of Northern Fulmar (Fulmarus glacialis) by 40% and nontarget fish species by 5–17%. Thus, best practices to prevent seabird mortalities in longline fisheries varied by species assemblage and fishery. Our results inform global efforts toward fisheries bycatch reduction by illustrating that successful conservation requires fishery-specific solutions, strong industry support, constant vigilance in analysis and reporting observer data, and ongoing outreach to fleets, especially to vessels with anomalously high BPUE.  相似文献   
44.
The U.S. Environmental Protection Agency (EPA) is in the process of designing a national network to monitor hazardous air pollutants (HAPs), also known as air toxics. The purposes of the expanded monitoring are to (1) characterize ambient concentrations in representative areas; (2) provide data to support and evaluate dispersion and receptor models; and (3) establish trends and evaluate the effectiveness of HAP emission reduction strategies. Existing air toxics data, in the form of an archive compiled by EPA's Office of Air Quality Planning and Standards (OAQPS), are used in this paper to examine the relationship between estimated annual average (AA) HAP concentrations and their associated variability. The goal is to assess the accuracy, or bias and precision, with which the AA can be estimated as a function of ambient concentration levels and sampling frequency. The results suggest that, for several air toxics, a sampling schedule of 1 in 3 days (1:3) or 1:6 days maybe appropriate for meeting some of the general objectives of the national network, with the more intense sampling rate being recommended for areas expected to exhibit relatively high ambient levels.  相似文献   
45.
用溶剂萃取-白土精制法对4种废机油进行了再生研究,萃取过程剂油质量比为3∶1,萃取温度为60℃,减压蒸馏回收溶剂。白土精制过程中白土质量为油质量的10%,精制温度为185℃。精制后4种废机油的密度、凝点、黏度、闪点、酸值等都有不同程度的改善。  相似文献   
46.
Combating climate change and protecting the environment is a significant topic amongst political leaders and concerned citizens across the globe. The degree to which individuals perceive green issues as important is connected to their politics, those subscribing to conservative ideologies being less supportive of pro-environmental initiatives and less concerned about climate change than those endsorsing liberal ideologies. Examining political ideology as a uni- and bi-dimensional construct, the present research investigated whether political liberals (vs. conservatives), those higher (vs. lower) in right-wing authoritarianism, and those higher (vs. lower) in social dominance orientation differ in their perceptions of the morality of green behaviours. In Studies 1 (= 200) and 2 (= 150), liberal (vs. conservative) ideologies related to perceiving pro-environmental behaviours as more moral. Further, in Study 2, the relation between ideology and perceptions of green behaviours as moral was explained by positive feelings associated with the self engaging in green behaviours.  相似文献   
47.
Riparian zones within the Appalachian Valley and Ridge physiographic province are often characterized by localized variability in soil moisture and organic carbon content, as well as variability in the distribution of soils formed from alluvial and colluvial processes. These sources of variability may significantly influence denitrification rates. This investigation studied the attenuation of nitrate (NO3- -N) as wastewater effluent flowed through the shallow ground water of a forested headwater riparian zone within the Appalachian Valley and Ridge physiographic province. Ground water flow and NO3- -N measurements indicated that NO3- -N discharged to the riparian zone preferentially flowed through the A and B horizons of depressional wetlands located in relic meander scars, with NO3- -N decreasing from > 12 to < 0.5 mg L(-1). Denitrification enzyme activity (DEA) attributable to riparian zone location, soil horizon, and NO3- -N amendments was also determined. Mean DEA in saturated soils attained values as high as 210 microg N kg(-1) h(-1), and was significantly higher than in unsaturated soils, regardless of horizon (p < 0.001). Denitrification enzyme activity in the shallow A horizon of wetland soils was significantly higher (p < 0.001) than in deeper soils. Significant stimulation of DEA (p = 0.027) by N03- -N amendments occurred only in the meander scar soils receiving low NO3- -N (<3.6 mg L(-1)) concentrations. Significant denitrification of high NO3- -N ground water can occur in riparian wetland soils, but DEA is dependent upon localized differences in the degree of soil saturation and organic carbon content.  相似文献   
48.
Citizen science has generated a growing interest among scientists and community groups, and citizen science programs have been created specifically for conservation. We examined collaborative science, a highly interactive form of citizen science, which we developed within a theoretically informed framework. In this essay, we focused on 2 aspects of our framework: social learning and adaptive management. Social learning, in contrast to individual‐based learning, stresses collaborative and generative insight making and is well‐suited for adaptive management. Adaptive‐management integrates feedback loops that are informed by what is learned and is guided by iterative decision making. Participants engaged in citizen science are able to add to what they are learning through primary data collection, which can result in the real‐time information that is often necessary for conservation. Our work is particularly timely because research publications consistently report a lack of established frameworks and evaluation plans to address the extent of conservation outcomes in citizen science. To illustrate how our framework supports conservation through citizen science, we examined how 2 programs enacted our collaborative science framework. Further, we inspected preliminary conservation outcomes of our case‐study programs. These programs, despite their recent implementation, are demonstrating promise with regard to positive conservation outcomes. To date, they are independently earning funds to support research, earning buy‐in from local partners to engage in experimentation, and, in the absence of leading scientists, are collecting data to test ideas. We argue that this success is due to citizen scientists being organized around local issues and engaging in iterative, collaborative, and adaptive learning.  相似文献   
49.
Despite a common understanding of the harmful impacts of Western conservation models that separate people from nature, widespread progress toward incorporating socioeconomic, political, cultural, and spiritual considerations in conservation practice is lacking. For some, the concept of nature-based solutions (NbS) is seen as an interdisciplinary and holistic pathway to better integrate human well-being in conservation. We examined how conservation practitioners in the United States view NbS and how social considerations are or are not incorporated in conservation adaptation projects. We interviewed 28 individuals working on 15 different such projects associated with the Wildlife Conservation Society's Climate Adaptation Fund. We completed 2 rounds of iterative coding in NVivo 12.6.1 to identify in the full text of all interview responses an a priori set of themes related to our research questions and emergent themes. Many respondents saw this moment as a tipping point for the field (one in which the perceived values of social considerations are increasing in conservation practice) (76%) and that social justice concerns and the need to overcome racist and colonial roots of Western conservation have risen to the forefront. Respondents also tentatively agreed that NbS in conservation could support social and ecological outcomes for conservation, but that it was far from guaranteed. Despite individual intention and awareness among practitioners to incorporate social considerations in conservation practice, structural barriers, including limited funding and inflexible grant structures, continue to constrain systemic change. Ultimately, systemic changes that address power and justice in policy and practice are required to leverage this moment to more fully address social considerations in conservation.  相似文献   
50.
Incorporating a social exchange perspective, we examined the joint impact of process fairness and turnover intentions on job performance. Results from two independent samples suggest that employee turnover intentions moderate relations between process fairness perceptions and employee job performance. Specifically, the positive effects of the two types of process fairness on performance were stronger for employees who planned to stay with the organization than for those who intended to leave. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
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